If amniotic fluid begins leaking during pregnancy, this may increase the baby’s risk of experiencing a birth injury. Some women find it difficult to determine if they are really leaking amniotic fluid or another substance (such as urine or vaginal discharge), so it is important to consult a doctor if there is any uncertainty.
Read on to learn more about the purpose of amniotic fluid, normal levels at various stages of pregnancy, and what leakage can indicate.
What is amniotic fluid?
During pregnancy, the baby floats in amniotic fluid, which is contained inside of the amniotic sac. The amniotic fluid appears within the first 12 days after conception. Early in pregnancy, it is made mostly of water produced by the mother. However, later in pregnancy, the baby begins to swallow the fluid and excrete it in the form of urine. By about 20 weeks of pregnancy, the amniotic fluid is made up entirely of fetal urine. It also contains important nutrients, antibodies, and hormones.
What is the purpose of amniotic fluid?
Amniotic fluid serves many functions. These include:
- Cushioning the fetus from physical pressures.
- Cushioning the umbilical cord from physical pressures (i.e. stopping it from becoming compressed, which can restrict the flow of oxygenated blood and nutrients to the baby).
- Keeping the baby warm.
- Preventing infection in the baby.
- Helping the baby’s lungs and digestive system develop. The baby breathes and swallows the amniotic fluid, thereby practicing using muscles in the respiratory and digestive tracts.
- Helping the baby’s muscles and bones develop. The fluid allows the baby to float and move around inside the amniotic sac, which promotes proper development.
- Preventing fingers and toes from growing together. The amniotic fluid lubricates the baby’s extremities. If there is not enough amniotic fluid, there may be webbing (1).
What is a normal amount of amniotic fluid?
The amount of amniotic fluid generally increases until approximately 36 weeks of pregnancy, when it reaches its highest point. Amniotic fluid levels throughout pregnancy may be as follows:
- Week 12 of pregnancy: 60 mL
- Week 16 of pregnancy: 175 mL
- Weeks 34-48 of pregnancy: 400-1,200 mL (2)
Toward the end of pregnancy, the amount of amniotic fluid should decrease in preparation for birth. Generally, the amniotic sac tears near the end of the first stage of labor. At this time, the remaining amniotic fluid begins to leak out through the cervix and vagina. This is often called a mother’s “water breaking” (1, 3). Some women will experience this as a sudden gush of fluid, but more often, it begins as a slow trickle (3). When the water breaks, it is important to get to the hospital as soon as possible. If a woman begins leaking amniotic fluid before the baby is at term, this can lead to premature birth and other complications (detailed in the next section). If the water breaks at term, this is a normal step of the birthing process and just means the baby is coming soon. However, hospitalization is still recommended for monitoring and medical care during the delivery process.
What can happen when amniotic fluid leaks?
Although a very small amount of amniotic fluid leakage may be okay, too much can result in oligohydramnios (an abnormally low level of amniotic fluid), and a number of other complications. These include:
- Premature birth
- Slowed fetal growth
- Labor difficulties. For example, the umbilical cord may become compressed, and the baby may be deprived of oxygen.
- Increased likelihood of cesarean delivery, which may be necessary to prevent fetal oxygen deprivation (birth asphyxia) and other complications.
- Infection. If there is a tear or puncture in the amniotic membranes, dangerous bacteria can enter the uterus and harm the baby. (2).
- Hypoxic-ischemic encephalopathy (HIE). This is a type of neonatal brain damage that may occur when the baby’s brain does not receive enough oxygenated blood flow (4).
Leaking amniotic fluid can indicate premature rupture of membranes (PROM), a complication in which the amniotic sac ruptures (the mother’s water breaks) before the baby is in the correct position for birth. PROM occurs in approximately two percent of pregnancies, and can result in infection, umbilical cord prolapse (when the cord descends the birth canal before or alongside the baby, possibly becoming compressed), and other issues.
PROM can also occur prematurely, in which case it is known as preterm premature rupture of membranes (PPROM). PPROM comes with the added risk of causing premature birth (5).
Oligohydramnios, PROM, PPROM, and other complications associated with leaking amniotic fluid can be very dangerous. These issues can cause serious birth injuries, illnesses, and lifelong disabilities, including the following (among others):
How do doctors measure amniotic fluid?
Throughout a woman’s pregnancy, her doctor should monitor the amount of amniotic fluid using ultrasound technology. There are two calculations that can be used: the amniotic fluid index (AFI) and the maximum vertical pocket (MPV) (2).
These tests can be used to diagnose oligohydramnios or polyhydramnios (abnormally high levels of amniotic fluid, the opposite of oligohydramnios). Both of these conditions serve as a warning sign that the mother and baby may be in danger.
Oligohydramnios occurs in about four percent of all pregnancies. It is more common in postterm pregnancies – that is, when a baby has not yet been delivered by 40 weeks. It can increase the risk of complications, especially umbilical cord prolapse. Sometimes, women with oligohydramnios will need cesarean deliveries. Doctors may also recommend an amnioinfusion (a procedure in which saline is infused into the uterus), increased hydration (either oral or through an IV), and bed rest (1).
Polyhydramnios occurs in about one percent of all pregnancies. Mild cases may resolve without treatment, but more severe cases can require amnioreduction, medications to reduce the amount of fetal urine (which can also put a fetus’s heart health at risk, so doctors must weigh the pros and cons very carefully, and closely monitor the baby), early induction, or bed rest (6).
How can I determine whether amniotic fluid is leaking?
The signs and symptoms of amniotic fluid leakage can be subtle. Healthline explains this with a useful analogy:
“Think of your amniotic sac like a water balloon. While it’s possible to break the water balloon, causing a strong gush of fluid (known as your water breaking), it’s also possible that a small hole could develop in the sac. This can result in a slow leak of amniotic fluid.”
During pregnancy, women may also experience leakage of urine (caused by the uterus pressing on the bladder) and excess vaginal fluid (which will help ease the birthing process). Distinguishing between these substances can be challenging, but the following are some general patterns:
- Urine usually has a smell and is yellow in color. Although pregnant women often do have some urine leakage, they generally maintain some level of control over when it is released, while this is not the case for vaginal fluid or amniotic fluid. Therefore, if you concentrate on “holding it,” and are still leaking fluid, it is likely not urine.
- Vaginal fluid is usually white or yellow-ish. It is unlikely to soak through underwear.
- Amniotic fluid has no smell. It can be clear, have white specks, or contain small amounts of mucus or blood. It is more likely than vaginal fluid to saturate underwear.
In order to determine whether a substance is amniotic fluid, Healthline recommends first emptying the bladder, and then wearing a sanitary pad or liner for 30 minutes to an hour. This will make it easier to examine (2).
When should I call a doctor?
If you believe your water has broken or have expelled a substantial amount of fluid, call your doctor immediately, because this may indicate your membranes have ruptured (1, 2).
You should also call your doctor immediately if the leaked fluid has a green or brownish yellow color. This may mean that your baby has defecated inside of the womb (or passed meconium); if this enters the baby’s lungs, it can be very dangerous. This complication is called meconium aspiration syndrome, and it requires prompt medical attention (1).
If you are unsure whether you have leaked amniotic fluid, the best thing to do is call a doctor right away. Remember that the distinction between these substances is not always obvious, and that it is your doctor’s job to help you when you have a concern!
What if my doctor doesn’t take my symptoms seriously?
Doctors who provide prenatal care should monitor their patients’ amniotic fluid volume via ultrasound. This is very important because the baby requires a certain amount of amniotic fluid in order to develop properly. If there is too little or too much, medical intervention may be necessary.
Failure to assess amniotic fluid volume during prenatal testing is negligence. If a doctor or nurse dismisses a pregnant woman’s concerns about amniotic fluid leakage, this is also negligence. If medical professionals fail to recognize/respond to amniotic fluid leakage, and this harms the baby, it is medical malpractice. When not managed appropriately, amniotic fluid leakage can lead to serious birth injuries and lifelong disabilities such as hypoxic-ischemic encephalopathy (HIE) and cerebral palsy.
Legal help for birth injuries stemming from malpractice
If your baby sustained a birth injury because doctors failed to respond to amniotic fluid leakage, the attorneys at ABC Law Centers (Reiter & Walsh, P.C.) may be able to help. We focus exclusively on birth injury cases, so we have the legal and medical expertise necessary to effectively advocate for our clients. Please reach out today for a free case review – in fact, you pay nothing throughout the entire legal process unless we win or favorably settle your case. Feel free to contact us in any of the following ways.
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- CRNP, L. S. (2018, June 27). Amniotic fluid: Functions and disorders. Retrieved April 11, 2019, from https://www.medicalnewstoday.com/articles/307082.php
- Leaking Amniotic Fluid: How to Tell. (n.d.). Retrieved April 11, 2019, from https://www.healthline.com/health/pregnancy/leaking-amniotic-fluid
- Signs of Labor. (2017, August 10). Retrieved April 11, 2019, from https://americanpregnancy.org/labor-and-birth/signs-of-labor/
- Martinez-Biarge, M., Diez-Sebastian, J., Wusthoff, C. J., Mercuri, E., & Cowan, F. M. (2013). Antepartum and intrapartum factors preceding neonatal hypoxic-ischemic encephalopathy. Pediatrics, 132(4), e952-e959.
- Premature Rupture of Membranes: First-Level Tests. (n.d.). Retrieved April 11, 2019, from https://www.healthline.com/health/pregnancy/premature-rupture-tests
- Polyhydramnios: High Amniotic Fluid During Pregnancy. (2017, June 26). Retrieved April 11, 2019, from https://americanpregnancy.org/pregnancy-complications/polyhydramnios-high-amniotic-fluid/